OCT B-Scans Can Stand in for ICGA to Find Polypoidal Lesions

In the absence of indocyanine green angiography (ICGA), B-scan optical coherence tomography (OCT) can be used to identify polypoidal choroidal vasculopathy (PCV) in patients with exudative age-related macular degeneration (AMD), according to study results published in Ophthalmology Retina.

While IGA is the standard of care used to diagnose PCV, it is not often available or ordered. Conversely, B-scan OCT is frequently available and can aid in the diagnosis of PCV. The polypoidal lesions are visualized as inverted U-shaped peaks in the retinal pigment epithelium with heterogeneous reflectivity, according to the findings. 

A team of investigators conducted a retrospective chart review to differentiate findings between the diagnosis of PCV or typical exudative AMD using ICGA and compared these findings with the OCT B-scan line scan in each cohort. 

A total of 112 eyes from 106 patients (mean age, 75.9 years) were evaluated for the presence of inverted U-shaped polypoidal lesions, the main differentiation between PCV and typical exudative AMD. The presence of subretinal fluid, macular edema or intraretinal edema, subretinal hyperreflective material, and retinal pigment epithelial detachment were assessed at baseline and 6 to 9 months after antiangiogenic therapy. The presence of polypoidal lesions before and after treatment was also evaluated. 

Of the cohort, 69 eyes were diagnosed with PCV and 43 eyes were diagnosed with neovascular AMD. Visual acuity at baseline was not significantly different between patient groups (P =.055); however, following treatment, eyes with PCV had significantly better vision than eyes with typical AMD without PCV (P =.008). 

At baseline, eyes with PCV had a significantly higher prevalence of subretinal fluid (P =.007) and branching retinal network (P <.001) compared with eyes with typical non-PCV exudative AMD. There was no significant difference in the prevalence of macular edema, subretinal hyperreflective material, or retinal pigment epithelial detachment between eyes with PCV and typical AMD at baseline. 

Patients were reevaluated 6 to 9 months after initiating anti-vascular endothelial growth factor (anti-VEGF) treatment. Following treatment, the prevalence of subretinal fluid significantly varied between eyes with PCV vs eyes with exudative AMD (33/69 eyes vs 12/43 eyes, respectively; P =.037). Branching retinal network was also still greater in eyes with PCV compared with AMD (27/42 eyes vs 0/43 eyes, respectively; P <.001). 

Results between groups for the presence of macular edema, subretinal hyperreflective material, or retinal pigment epithelial detachment were not significantly different at 6 to 9 months after treatment. 

Following B-scan OCT, the presence of inverted U-shaped elevations of the retinal pigment epithelium with heterogeneous reflectivity was identified in 39 of 69 eyes (56.5%) with PCV and 1 of 43 eyes (2.3%) with AMD at baseline. After treatment, the elevations corresponding to polypoidal lesions were not present in eyes with typical AMD and still present in 17 of 69 eyes (24.6%) with PCV (P <.001). After anti-VEGF treatment, visible lesions in eyes with PCV declined by 56.4%. 

Although anti-VEGF resistance is more common in eyes with PCV compared with non-PCV AMD, the study recommends reviewing pretreatment B-scan OCT before anti-VEGF therapy, as lesions decrease after treatment. 

“Often, eyes with a poor response to anti-VEGF therapy will be missed if the B-scan OCT is only evaluated after anti-VEGF therapy,” the researchers explain. “The B-scan OCT can help guide therapy in eyes with exudative AMD by showing typical findings of PCV, thereby allowing alternative therapy such as combination [photodynamic therapy] and antiangiogenic therapy to be used either primarily or after eyes exhibit anti-VEGF resistance,” according to the investigation. 

Reference 

Kokame GT, Omizo JN, Kokame KA, Yamane ML. Differentiating exudative macular degeneration and polypoidal choroidal vasculopathy using optical coherence tomography B-scan. Ophthalmol Retina. Published online May 19, 2021. doi:10.1016/j.oret.2021.05.009